England’s Jenny Duncalf battled for 55 minutes to upset third seed Rachael Grinham in the Women’s Texas Open to reach the last four of the $57,000 WISPA World Tour Gold squash event at Life Time Fitness in Plano, near Dallas, USA.

The fifth seed from Harrogate in Yorkshire recovered from a game behind to beat Grinham 8-11, 11-9, 11-7, 8-11, 11-9 - recording her third successive victory over the world number three from Australia since May last year.

The win takes Duncalf into her second surprise semi in less than two weeks - and it was an upset over Rachael’s sister Natalie Grinham that led the England number one into the last four of the Cayman Islands Open: “It was a risk to play in Cayman, as being fifth seed wasn’t ideal - but if you want to try and beat these players you have to put yourself in the mix,” explained Duncalf.

“Rachael has a really good touch, and puts the unexpected one in short and it had to be in the back of my mind to cover it.”

Grinham senior, who clearly found the court’s unusual clear glass right side wall difficult, added: “She is moving very well these days, which is a bit of a pain! It is a bit hard as the court is tricky. The forehand side is not so easy, but she held it together better than I did.”

Duncalf now faces favourite Nicol David, the world number one from Malaysia who beat France’s No8 seed Isabelle Stoehr 11-5, 11-8, 11-7.

Natalie Grinham made up for her Grand Cayman disappointment by beating England’s sixth seed Alison Waters 11-5, 11-9, 13-11 in an earlier quarter-final.

The fourth seed from the Netherlands now meets Natalie Grainger - though the second seed from the USA had to fight back from 1-8 down in the second game before going on to beat unseeded Mexican Samantha Teran 11-5, 13-11, 11-9.